Electric water heater



Aug. 26, 1947. J, GABLER 2,426,302

ELECTRIC WATER HEATER Filed May 18, 1945 2 Sheets-Sheet l F g/i 152 Fen Z0 r IQ/SW 5102 In: rr-y 9 1947- J GABLER 2,426,302

ELECTRIC WATER HEATER Filed May 18, 1945 2 Sheets- Sheet 2 Erna Zor 4/0 GABLf/Q Patented Aug. 26, 1947 UNITED STATES PATENT OFFICE ELECTRIC WATER HEATER John Gabler, London, England Application May 18, 1945, Serial No. 594,430 In Great Britain May 22, 1944 6 Claims. 1

This invention relates to electric water heaters.

One object of the invention is to provide an electric water heater in which, when out of action, no water is retained in contact with the heating surfaces.

A further object of the invention is to provide a water heater consisting of a plurality of independent heating units over which the water to be heated flows in a thin film and in a uniform manner.

Still a further object of the invention is to provide an electric water heater in which the heating elements only operate when water is introduced into the apparatus.

With the foregoing object and other objects in view, an electric water heater in accordance with the invention comprises a plurality of upstanding tubular casings, closed at their upper ends and containing electric heating elements, with means for closing the circuit of such elements by the pressure of water delivered to the water heater, means for distributing such water to fall on to the closed upper ends of the tubular casings and means for delivering water from and heated by the casings.

The upstanding tubular casings are mounted on a base plate which forms the bottom of a closed chamber enclosing the tubular heater casings. The upper portion of this chamber contains a closed shallow tank, to which cold water is supplied and from which such water overflows down an upstanding -weir pipe above and dropping the water on to each tubular heater casing, the closed upper end of which conveniently is concave.

Hot water flows out of an outlet at the bottom of the chamber.

In order to delay the flow of water down the outer surface of each tubular heater casing, each thereof may provide a helical path for the water by a helically wound wire, of square or other cross section, thereon, or by a helical fin.

Water admitted to the distributing tank can be arranged to close the circuit of the electric heater elements by the main pressure of the water, choked by having to pass a spring-pressed non-return valve, displacing a diaphragm or flexing a Bourdon tube which, through linkage raises a mercury switch to the circuit closing position. In order to cause the switch automatically to open the heater circuit, it is pivoted at the end remote from that raised by the diaphragm or Bourdon tube, so that on water no longer being admitted to displace the diaphragm, the support by the latter of the mercury switch is withdrawn, and the mercury switch drops under the influence of its own weight.

In the accompanying drawings, which illustrate diagrammatically and by way of example, one embodiment of the invention:

Fig. 1 is a transverse vertical section;

Fig. 2 is a longitudinal vertical section;

Fig. 3 is a plan view with the cover of the casing removed; and

Fig. 4 is a detail.

The water heater shown consists of a battery of five tubular heating bodies l. 2, 3, 4, 5. The heating body I is shown in vertical section. Each heating body comprises a tubular wire-wound heating element 6 which is shown in elevation in the heating body 2. Each heating element 6 is carried by a rod 1 and is clamped in position between two insulating discs 8, 8 by a terminal nut 9. Each heating element 6, is also enclosed in a tubular casing l0 having a dished closed upper end ll. Each casing It is in turn closely surrounded by a withdrawable outer tubular casing l2 having a similarly dished closed upper end and wound with a wire helix I3.

The five heating bodies I, 2, 3, 4, 5 are brazed to a metal plate M to which is secured a base plate [5 of insulating material. The whole assembly is enclosed in an inner metal casing It, the lower end of which is brazed to the metal plate I 4.

Projecting into the casing i6 is a water inlet tube I1 whilst a water outlet tube [8 is provided at the underside of the opposite end of the casing I5. These tubes are brazed to the casin l6 and serve to support the same. The tubes I! and I8 are secured to a stout bracket l9 by nuts 26, 2|, while the upright end of the bracket I9 is fixed by screws 22 to a back plate 23 which in turn is secured to a dished mounting bar 24 by a screw 25. At its upper end the casing I 6 is secured to the back plate and mounting bar by a nut 26.

The upper part of the casing l6 carries a distributing trough 21 which carries five overflow weir pipes 28 of the chamfered and slotted construction shown in Fig. 4.

The trough 21 is clamped to the inlet tube I! by clamping nuts 29 and is provided with a lateral overflow tube 30 leading outside the casing i5. Said tube 30 has a cut-out portion 31 permitting escape of steam from the casing l6. The top of the casing I 6 is provided with a dished cover 32 secured thereto by nuts 33 and 26.

At the inlet end of the tube l! is a ball valve s4 comprising a ball 35 loaded b a compression spring 35. Beneath said ball valve is a branch tube 31 leading to a Bourdon tube 38. Pivoted to the end of said Bourdon tube 38 is one end of a link 39, the other end of which link is connected to a screw 40 which actuates the spindle M of the holder of a mercury switch 42 which is mounted on a bracket 43.

Current is supplied to the heating bodies I, 2, 3, l, 5 through current leads 44, 45. The whole apparatus is covered b an outer casing 46 which is secured at its top to the cover 33 of the casing l6 by a screw 41 and at its lower end to the bracket l9 by a screw 48;

The apparatus operates as follows:

When connected to a water main and to a source of current and when the water is turned on, th water entering the inlet conduit 11 encounters the resistance of the ball valve 34, being thereby forced into the branch 31 and Bourdon tube 38 which is thus flexed and thereby tilts the mercury switch 42 into the on position thereby heating up the heating bodies I, 2, 3, 4, 5. When the pressure of the incoming water has overcome the resistance of the ball valve 34, the water rises through the tube H into the trough 27 rising therein until it encounters the slots in the weirs 23. It then flows through the Weirs 28 on to the dished top ends of the heating bodies I to 5, and

from thence flows down in a helical path along the wire helices l3, thereby becoming rapidly and uniformly heated. The hot water arriving at the bottom of each heating body then issues through as outlet pipe l8.

When the inlet of water to the apparatus is stopped, the pressure on th Bourdon tube is released and the same returns the mercury switch 42 into the off position. The hot water immediately drains away through the outlet l8 whilst any residual moisture remaining in the apparatus is converted by the residual heat of the heating bodies I to '5, into steam which issues through the tube 36, thus leaving the apparatus completely dry.

In order to ensure freedom of the heating bodies I to 5 from scale the outer casings l2 are made removable for cleaning purposes. That of the heating bod 3 is shown partially withdrawn and broken away.

I claim:

1. In an electric water heater, a closed bottomed vessel, a water outlet pip leading from the bottom of said vesseha plurality of closed topped inner tubular casings upstanding from said bottom of and within said vessel, an electric heater element in each said inner tubular casing, a withdrawable outer tubular casing closely surrounding each. said inner tubular casing, a trough above said tubular casings, an overflow weir pipe in the bottom of said trough above each said tubular casing, a water inlet pipe leading to said trough, a loaded valve in said water inlet pipe, a pressure-deflected device connected to said water inlet pipe in advance of said valve, and an electric switch in the circuit of said heater elements operated by said pressure-deflected device.

2. In an electric water heater, a closed bottomed vessel, a water outlet pipe leading from the bottom of said vessel, a plurality of closed topped inner tubular casings upstanding from said bottom of and within said vessel, an electric heater element in each said inner tubular casing, a withdrawable outer tubular casing closely surrounding each said inner tubular casing, a trough above said tubular casings, an overflow weir pipe in the bottom of said trough above each said tubular casing, a water inlet pipe leading to said trough, a loaded valv in said Water inlet pipe, a pressure-deflected device connected to said water inlet pipe in advance of said valve, and a mercury switch in the circuit of said heater elements connected to and operated by said pressure-deflected device.

3, In an electric water heater, a closed bottomed vessel, a water outlet pipe leading from th bottom of said vessel, a plurality of closed topped inner tubular casings upstanding from said bottom of and within said vessel, an electric heater element in each said inner tubular casing, a withdrawable outer tubular casing closely surrounding each said inner tubular casing, a trough above said tubular casings, an overflow weir pipe in the bottom of said trough above each said tubular casing, a water inlet pipe, leading to said trough, a loaded valve in said water inlet pipe, a Bourdon tube connected to said water inlet pipe in advance of said valve, and an electric switch in the circuit of said heater elements operated by said Bourdon tube,

4. In an electric water heater, 2. closed bottomed .vessel, a water outlet pipe leading from the bottom of said vessel, a plurality of closed topped inner tubular casings upstanding from said bottom of and within said vessel, an electric heater element in each said inner tubular casing, a withdrawable outer tubular casing closely surrounding each said inner tubular casing, a trough above said tubular casings, an overflow weir pipe in the bottom of said trough above each said tubular casing, a water inlet pipe, leading to said trough, a loaded valve in said water inlet pipe, at Bourdon tube connected to said water inlet pipe in advance of said valve, and a mercury switch in the circuit of said heater elements and connected to and operated by said Bourdon tube,

5. In an electric Water heater, a closed bottomed vessel, a water outlet pipe leading from the bottom of said vessel, a plurality of closed topped inner tubular casings upstanding from said bottom of and within said vessel, an electric heater element in each said inner tubular casing, a withdrawable outer tubular casing closely surrounding each said inner tubular casing, a wire helix closely surrounding each said outer tubular casing, a trough above said tubular casings, an overflow weir pipe in the bottom of said trough above each said tubular casing, a water inlet pipe leading to said trough, a loaded valve in said inlet pipe, a pressure-deflected device connected to said water inlet pipe in advance of said valve, and an electric switch in the circuit of said heater elements operated by said pressure-deflected device.

6. In an electric water heater, a closed bottomed vessel, a Water outlet pipe leading from the bottom of said vessel, a plurality of closed topped inner tubular casings upstanding from said bottom of and within said vessel, an electric heater element in each said inner tubular casing,

I 2,426,302 5 6 a with drawable outer tubular casmg closely sur- REFERENCES CITED rounding each said inner tubular caslng, a wire helix closely surrounding each said outer tubular h f ll wm r f r n es r of record 111 the casing, a trough above said tubular casings, an file Of s p t OVeIfiQW Weir pipe in the bottom Of Said trough above each said tubular casing, a Water inlet pipe leading to said trough, a loaded valve in said inlet Number Name Date pipe, a Bourdon tube connected to said water 944950 Rams 21, 1909 inlet pipe in advance of said valve, and a mer- 576,208 Lozier 2, 1397 cury switch in the circuit of said heater elements 10 15481779 Falkenberg 4, 1925 and connected to said Bourdon tube. 11759331 Rosenberger May 1930 1,977,156 Staley Oct. 16, 1934 JOHN GABLER 2,081,206 Parker May 25, 1937 2,284,414 Gammon May 26, 1942 

